Insulating Floors in Historic Buildings

This page provides advice on improving the thermal performance of floors by adding insulation. The majority of older buildings have either a suspended timber floor or a solid floor which might have a finish such as tiling or stone. Often these types of floor are used in different parts of the same building.

Suspended timber floors

Suspended timber floors can be a significant source of heat loss particularly if there are gaps between floorboards allowing draughts.

Draughts between boards can be removed relatively easily by filling gaps. Adding insulation can be more difficult as invariably this involves taking up most of the boards to access the void below. Many older floors can be easily damaged so great care needs to be taken when removing and replacing boards.

Solid floors

The energy saved by insulating solid floors can in many cases be quite marginal and not as cost effective as many other types of thermal upgrading. The reason for this is partly the cost and disruption of the work but also a typical solid floor already provides a degree of insulation mainly because the ground beneath maintains a stable temperature. However, where an existing floor is being taken up, replaced or repaired then it can be a good opportunity to improve its thermal performance.